Desenvolvimento de um sistema de controle para a temperatura de líquido refrigerante aplicado em motores de combustão interna

Abstract

The present work proposes the development of an internal combustion engine temperature control system, involving the implementation of a PI (Proportional-Integral) controller to regulate the speed of a DC motor, which is applied to the cooling system's electric fan. Pulse Width Modulation (PWM) analysis was performed using an ESP32 microcontroller and an H-bridge. Knowing that the system has a complex characteristic for mathematical modeling, a practical efficiency test was chosen, as access to a test rig was available. The system's step response was used to generate the transfer function. After obtaining the mathematical model, software such as PSIM and MATLAB were used for the closed-loop control simulation, as well as the tuning of the controller gains. The results obtained in the simulation proved adequate for the experimental implementation, in the power circuit, the H-bridge and the DC motor functioned appropriately, following the motor's nominal rotational speed, voltage, and current. Following the necessary adjustments to the controller gains, along with the insertion of a comparator, it was possible to carry out practical tests on a bench and on a real test rig. The simulation and experimental results demonstrated that the temperature control is viable, allowing for practical application in the automotive sector.